Realism in evaluation represents a paradigm through which the world is seen as an open system of dynamic structures, mechanisms and contexts that intricately influence the change phenomena that evaluations aim to capture. Realistic evaluators argue that RCTs fail to test hypotheses rooted in theory and embrace a crude notion of causality based on comparison groups and statistical association rather than understanding mechanisms. They argue that evaluators must develop a priory theories about how, for whom and under what conditions interventions will work and then use observational data to examine how context and intervention mechanism interact to generate outcomes. While we dispute the realists’ rejection of experimental designs in the social sciences, we agree with their arguments concerning the need for evaluation: to examine how, why and for whom interventions work; to give more attention to context; and to focus on the elaboration and validation of program theory.

RCTs themselves could contribute to a realist approach to evaluation.We examine the extent to which some RCTs are already embracing many of these issues and, bringing together some of these existing innovations alongside our own ideas, sketch out what ‘realist RCTs’ might look like. We argue that it is possible to benefit from the insights provided by realist evaluation without relinquishing the RCT as the best means of examining intervention causality.

RCTs aim to generate minimally biased estimates of intervention effects by ensuring that intervention and control groups are not systematically different from each other in terms of measured and/ or unmeasured characteristics. Random allocation is widely regarded as ethical if there is uncertainty about whether inter- vention confers significant benefit.

The most prominent exponents of realist evaluation are criminologists Ray Pawson and Nick Tilley, who criticize the RCT approach for its positivist assumptions, and suggest alternatives based on a realist perspective.

This paper is very judgmental and I believe that referencing this paper should be avoided.